Computers Merit Badge


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Computers Merit Badge

  1. 1. Computers Merit Badge Christopher Strauss Frontier Trails District Troop 132
  2. 2. Computers Merit Badge Webs <ul><li>Course web for this class </li></ul><ul><ul><li>Computers Merit Badge Course Web </li></ul></ul><ul><ul><ul><li>Computers Merit Badge Requirements </li></ul></ul></ul><ul><ul><ul><li>Computers Merit Badge Proof of Completion </li></ul></ul></ul><ul><ul><ul><li>Instructor's Course Outline </li></ul></ul></ul><ul><ul><ul><li>Computers Merit Badge Take-home Worksheet </li></ul></ul></ul><ul><li>Resource Webs (listed on the Course Web) </li></ul><ul><li>Many other web resources are available – just search on computers or some other term in your favorite web search engine </li></ul>
  3. 3. History of Computers - Abacus <ul><li>The first true calculating machine (before 400 BC) was the abacus </li></ul>
  4. 4. Napier’s Bones (circa 1617) <ul><li>The Scottish inventor of logarithms went on to construct calculating rods (made from bone) that perform multiplication and division by simply adding and subtracting </li></ul><ul><li>Led to slide rules (1621 – Fr. Oughtred) </li></ul>
  5. 5. Charles Babbage’s “Difference Machine” and “Analytical Engine” <ul><li>1822 and 1833 designs </li></ul><ul><li>Prototype for modern computers </li></ul><ul><li>Four parts: Input device, memory (store), processor (mill), and an output device </li></ul><ul><li>The difference machine was actually built recently at MIT.. and worked!! </li></ul>
  6. 6. Herman Hollerith’s Punch Cards <ul><li>Developed to win a contest by the Census Bureau to improve census data processing after the 1880 census had taken seven years to tabulate. </li></ul><ul><ul><li>They were used successfully in the 1890 U. S. Census </li></ul></ul><ul><li>The concept was not THAT new – in France in 1801, Joseph-Marie Jacquard invented an automatic loom using punched cards for the control of the patterns in the fabrics. </li></ul><ul><li>Herman Hollerith later formed the company that became IBM (International Business Machines Corporation). </li></ul>
  7. 7. Colossus Mark I (England), Harvard Mark I, ENIAC, EDVAC <ul><li>World War II: computers were developed to break German and Japanese message codes and create firing tables </li></ul><ul><li>Technologies: central processors were made up of vacuum tubes </li></ul><ul><li>Beginning with the Harvard Mark I , they could be re-programmed by re-wiring with plugs like a switchboard, or with paper punch tape </li></ul>
  8. 8. De-bugging computers is born <ul><li>9 September 1945 –Ensign Grace Murray Hopper (RADM, USN) removed the first “bug” from a electromagnetic relay in the Harvard Mark II where it had been smashed, halting the computer. She taped the moth to a page the log book. </li></ul>
  9. 9. Technological Breakthroughs <ul><li>1947 - William Shockley, John Bardeen, and Walter Brattain invent the &quot; transfer resistance &quot; device, later to be known as the “ transistor ,” to replace vacuum tubes </li></ul><ul><li>1951 – Magnetic-core memory also replaces tubes, making real-time memory use practical </li></ul>
  10. 10. Remington Rand UNIVAC – 1951 - Delivered to the Census Bureau <ul><li>First mass-produced computer (46 made) </li></ul><ul><li>The size of a one-car garage (14’ x 8’ x 8.5’) </li></ul><ul><li>5,200 vacuum tubes required a chilled water air conditioning system </li></ul><ul><li>Government, GE, insurance companies, DuPont (scientific) </li></ul><ul><li>1956 Concordance of the Bible (6 mos. vs. 30 yrs) </li></ul>
  11. 11. Integrated Circuit <ul><li>1958 – Jack Kilby created the first “ integrated circuit ” at Texas Instruments to prove that resistors and capacitors could exist on the same piece of semiconductor material. His circuit consisted of a sliver of poisonous germanium with five components linked by wires. Germanium was soon replaced by silicon (1961). </li></ul>
  12. 12. Microprocessors <ul><li>1971 - Federico Faggin, Ted Hoff, and others at Intel designed the 4004 microprocessor while building a custom chip for Busicom, a Japanese calculator maker. The 4004 had 2,250 transistors, handling data in four-bit chunks, and could perform 60,000 operations per second. </li></ul>
  13. 13. Electronic Hobby Computers evolve into Personal Computers!! <ul><li>1975 - Electronics hobbyists buy the earliest personal computer </li></ul><ul><ul><li>MITS Altair 8800 (Intel 8080) </li></ul></ul><ul><li>1976 - Consumer computers arrive after several companies begin large scale manufacturing </li></ul><ul><ul><li>1976 - Apple Computer Apple II </li></ul></ul><ul><ul><li>1977 - Radio Shack TRS-80 </li></ul></ul><ul><ul><li>Commodore PET </li></ul></ul><ul><ul><li>Heath H8, H9 </li></ul></ul><ul><ul><li>1981 – IBM PC </li></ul></ul>
  14. 14. Types of Computers <ul><li>Categories </li></ul><ul><ul><li>Special purpose (digital watch, emission control computer, home security system) </li></ul></ul><ul><ul><li>General purpose (Mainframes, Minis, PCs) </li></ul></ul><ul><li>Sizes </li></ul><ul><ul><li>Supercomputers (beginning with the CRAY I in 1976!! - massively parallel processing) </li></ul></ul><ul><ul><li>Mainframes (multi-user IBM, DEC, NCR, etc.) </li></ul></ul><ul><ul><li>Minicomputers (multi-user DEC, Sun, file servers) </li></ul></ul><ul><ul><li>Microcomputers (single-user personal computers) </li></ul></ul><ul><ul><li>NEW – wearable computers now in development </li></ul></ul>
  15. 15. Uses for Computers <ul><li>For supercomputers… </li></ul><ul><ul><li>Weather forecasting, satellite tracking, research </li></ul></ul><ul><li>For mainframe computers… </li></ul><ul><ul><li>Banking, library automation, flight scheduling, census </li></ul></ul><ul><li>For minicomputers… </li></ul><ul><ul><li>Operate manufacturing plants, track orders and inventory, multi-user applications, web, email, and database services </li></ul></ul><ul><li>For microcomputers… </li></ul><ul><ul><li>Spreadsheets, word processing, graphics, games, communications </li></ul></ul>
  16. 16. Parts of a Computer <ul><li>Central Processing Unit (CPU) is the “brain,” and is some brand of microprocessor chip </li></ul><ul><ul><li>Intel 4004 – 2,250 transistors; 8088 – 40,000; 80486 – 1 million; Pentium – 7 million; Pentium II – 30 million </li></ul></ul><ul><li>The CPU is normally mounted in a plug-in socket on the motherboard , a circuit board tying everything in the computer together via an electronic “bus” </li></ul><ul><li>Co-processors are used to offload computing tasks from the CPU, such as mathematics and graphics </li></ul><ul><li>Random Access Memory (RAM) and Read-Only Memory (ROM) are also mounted here </li></ul><ul><ul><li>ROM is permanent, often re-writable (CMOS) </li></ul></ul><ul><ul><li>RAM is transient unless permanently powered (Palm) </li></ul></ul><ul><li>See PC Tech Guide for more details </li></ul>
  17. 17. Schematic Diagrams <ul><li>What's in that Box web </li></ul><ul><li>Click-n-learn Guide to PC </li></ul><ul><li>PC Tech Guide </li></ul><ul><li>Dave's Guide </li></ul>
  18. 18. Input Devices (digitizers) <ul><li>Keyboard (QUERTY, Dvorak, custom – an alphanumeric symbol digitizer) </li></ul><ul><li>Mouse and other Pointing devices </li></ul><ul><ul><li>Trackball, joystick, pressure-sensitive tablet, touch screen – a location digitizer </li></ul></ul><ul><li>Sound digitizer (microphone, MIDI device) </li></ul><ul><li>Scanner (an image digitizer) </li></ul><ul><li>Sensor (temperature, light, moisture, smoke, movement, or other environmental digitizer) </li></ul>
  19. 19. Magnetic Storage <ul><li>Sequential Access </li></ul><ul><ul><li>Magnetic Tape </li></ul></ul><ul><ul><ul><li>Reel-to-reel or cassette </li></ul></ul></ul><ul><ul><ul><li>Original microcomputer media, now used for backups </li></ul></ul></ul><ul><li>Random Access </li></ul><ul><ul><li>Floppy Disk (8”, 5 ¼”, 3.25”, etc.) </li></ul></ul><ul><ul><ul><li>Magnetic powder coating on flexible disk in sleeve </li></ul></ul></ul><ul><ul><ul><li>Drive contains an actuator and read-write head on arm </li></ul></ul></ul><ul><ul><li>Hard Disk </li></ul></ul><ul><ul><ul><li>Magnetically coated metallic platters on high-speed spindle </li></ul></ul></ul><ul><ul><ul><li>Drive actuator with many floating read-write heads on arms </li></ul></ul></ul><ul><ul><li>For more information see How Hard Drives Work and PC Tech Guide (where this diagram came from ----- >) </li></ul></ul>
  20. 20. Optical Storage <ul><li>CD-ROM (Compact-Disc Read-Only Memory) </li></ul><ul><ul><li>Write laser burns pits into the surface of the disk </li></ul></ul><ul><ul><li>Read laser bounces light off the pitted surface </li></ul></ul><ul><ul><li>WORM – Write Once Read Many, or CD-R </li></ul></ul><ul><ul><li>Newest formats: CD-RW, DVD, DVD-RW </li></ul></ul><ul><li>Capacity (newer media have higher capacities) </li></ul><ul><ul><li>Compare the CD-ROM surface (left) to the DVD surface (right) </li></ul></ul><ul><ul><li>For more information see How CDs Work and PC Tech Guide </li></ul></ul>Motion picture 4.5 gigabytes DVD-5 270,000 pages 540 megabytes CD-ROM 40,000 pages 80 megabytes Hard Drive 720 typed pages 1.4 megabytes High-density disk Equivalent Size Typical Capacity Medium
  21. 21. Output Devices <ul><li>Printers (the first output device) and Plotters </li></ul><ul><ul><li>Impact (daisywheel) and dot-matrix </li></ul></ul><ul><ul><li>Thermal (early BW and color) </li></ul></ul><ul><ul><li>Laser (highest quality, BW and color) </li></ul></ul><ul><ul><li>Plotters (pens on moving arms like seismographs) </li></ul></ul><ul><ul><li>Ink-jet (color plotters lead to printers, some also thermal) </li></ul></ul><ul><li>Monitor </li></ul><ul><ul><li>Analog: CRT (cathode-ray tube) – the “monitor” </li></ul></ul><ul><ul><li>Digital: LCD (liquid-crystal display) screens </li></ul></ul><ul><li>Sound Card (digital to analog converter) </li></ul><ul><li>Modem (modulator-demodulator; another digital to analog signal converter) </li></ul>
  22. 22. Computer Software <ul><li>Three main categories of programs </li></ul><ul><ul><li>Operating Systems </li></ul></ul><ul><ul><ul><li>Control all of the computer’s basic operations </li></ul></ul></ul><ul><ul><ul><ul><li>Input, output, file, memory, and task management </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Text-based (UNIX, CP/M, MS-DOS) and graphical (GUI) (Xerox Star, Macintosh, X-Windows, Microsoft Windows) </li></ul></ul></ul></ul><ul><ul><li>Application Programs </li></ul></ul><ul><ul><ul><li>Perform specific jobs or tasks with the computer </li></ul></ul></ul><ul><ul><ul><ul><li>Database manager, spreadsheet, word processor, page layout, graphics, CAD, animation, sound, communications </li></ul></ul></ul></ul><ul><ul><li>Programming Languages </li></ul></ul><ul><ul><ul><li>A program used to develop and write other programs and applications </li></ul></ul></ul>
  23. 23. Programming Languages <ul><li>Machine code (low-level code, object code) </li></ul><ul><ul><li>Specific to the microprocessor (Z80, 6502, 8088) </li></ul></ul><ul><ul><li>An instruction set to move decimal data through the CPU </li></ul></ul><ul><ul><li>Assembly language is a mnemonic symbol set for the CPU </li></ul></ul><ul><li>High-level languages </li></ul><ul><ul><li>Source code </li></ul></ul><ul><ul><ul><li>COBOL, FORTRAN, BASIC, Pascal, Ada, C, VB </li></ul></ul></ul><ul><ul><ul><li>Object oriented (modular) languages – C++, Java </li></ul></ul></ul><ul><ul><li>Translated by a compiler into object code before run-time </li></ul></ul><ul><ul><li>… or translated by an interpreter into object code at run-time (MUCH slower – Basic, scripting languages like Perl, JavaScript, VBScript, HTML, XML) </li></ul></ul>
  24. 24. Programming Language Use <ul><li>COBOL (COmmon Business Oriented Language) for business data processing </li></ul><ul><li>FORTRAN (FORmula TRANslator) for scientific and engineering problems </li></ul><ul><li>BASIC (Beginner’s All-Purpose Symbolic instruction Code) for educational and personal computing (NOTE: Visual Basic is now widely used in business office automation to build client-server applications and integrate them with office applications) </li></ul><ul><li>Pascal for educational and general-purpose (led to Ada, now widely used in government and defense contracts) </li></ul><ul><li>C, C++ and Java for cross-platform portable, object oriented (reusable modules) application and game development </li></ul><ul><li>Perl, JavaScript, VBScript, and MANY other scripting languages, all interpreted, for system administration, web pages, data work </li></ul>
  25. 25. Data Storage: Text & Numbers <ul><li>Computers use binary numbers (1’s and 0’s) to store data. One digit is a bit; four are a nibble, eight are a byte. Integers (whole numbers) can be stored directly in binary bytes. </li></ul><ul><ul><li>0 = 00000000 3 = 00000011 </li></ul></ul><ul><ul><li>1 = 00000001 4 = 00000100 </li></ul></ul><ul><ul><li>2 = 00000010 5 = 00000101 </li></ul></ul><ul><li>A byte can be translated into a decimal number by adding up the decimal values indicated by “1’s” in the binary number </li></ul><ul><ul><li>128 64 32 16 8 4 2 1 decimal values </li></ul></ul><ul><ul><li>0 0 0 0 0 0 0 0 binary places (8-bit) </li></ul></ul><ul><ul><li>0 0 1 0 1 0 1 0 binary equals 42 decimal ( 32+8+2 ) </li></ul></ul><ul><li>Additional translation schemes have been developed to match character sets to decimal and binary, such as ASCII & EBCDIC </li></ul>
  26. 26. Data Storage: Text & Numbers <ul><li>Text and numeric characters are stored as ASCII (American Standard Code for Information Interchange ) values, consisting of 128 different decimal codes. Extended ASCII goes to 256 codes. </li></ul><ul><li>ASCII translates each letter and number into a binary byte (8 bits) that the computer understands. </li></ul><ul><ul><li>&quot;1&quot; is ASCII decimal “49” and binary 00110001 </li></ul></ul><ul><ul><li>&quot;A&quot; is ASCII decimal “65” and binary 01000001 </li></ul></ul><ul><ul><li>“ &” is ASCII decimal “38” and binary 00100110 </li></ul></ul><ul><ul><li>“ z” is ASCII decimal “122” and binary 01111010 </li></ul></ul>
  27. 27. ASCII Translation S 1010011 20 T 1010100 21 U 1010101 22 O 1001111 18 C 1000011 3 S 1010011 20 Y 1011001 26 O 1001111 18 B 1000010 2 Alphanumeric ASCII Binary ASCII Decimal
  28. 28. Data Storage: Pictures <ul><li>Computer pictures are stored as millions of colored dots called “ pixels ” (picture elements) that have to be translated to an analog signal for an analog CRT monitor to display them (LCD panels are already digital so no translation is required). </li></ul><ul><li>Each black & white pixel is either on or off; each color pixel is three dots, Red, Green, and Blue (RGB) that combine to create a color. Color pixel combinations range from 256 possible colors to over 16.8 million colors (real, or true color). </li></ul><ul><li>The more pixels a picture has, the better it looks (it has a higher resolution). Each pixel has an associated color and location on the screen expressed in binary terms. </li></ul><ul><li>When stored, each pixel’s information is saved to disk separately . In a true color (32 bit) pixel, 4 bytes are used to store the color information for each dot in the pixel. For a 1600x1200-pixel display this is 8-million bytes of video memory, stored as one 8mb disk file! (bit-depth in How Computer Monitors Work ) </li></ul><ul><ul><li>For more detailed information see How Graphics Cards Work </li></ul></ul>
  29. 29. A pixel
  30. 30. Color Displays Red Green Blue Purple Yellow
  31. 31. Color Displays Black White
  32. 32. Intensity - Millions of colors Red= Blue= Green= 255 255 255 128 128 128 10 168 64
  33. 33. CRT Display LCD Display <ul><li>CRT </li></ul><ul><ul><li>Dot Trio </li></ul></ul><ul><ul><li>Aperture Grill </li></ul></ul><ul><ul><li>Slotted Mask </li></ul></ul><ul><ul><li>Enhanced Dot Pitch </li></ul></ul><ul><li>LCD </li></ul>
  34. 34. Data Storage: Sound <ul><li>Normal sound is made up of waves or vibrations.  Each sound wave has a wavelength (how far between the waves) and amplitude (how high the wave is). </li></ul><ul><li>A mixed, analog waveform signal comes in to the sound card from a source (microphone) and is processed in real-time by an analog-to-digital converter (ADC) circuit chip to create a binary (digital) output of 1s and 0s. This is done at a specified interval or “sampling frequency” (i.e., 1/10th of a second).  </li></ul><ul><li>The digital output from the ADC is further processed and compressed by the digital sound processor (DSP), and the output from the DSP is sent to the computer's CPU via the sound card connections and the data bus on the motherboard. </li></ul><ul><li>Digital sound data is processed by the CPU and sent to the hard-disk controller to be recorded on the hard-disk drive as a wav file . </li></ul><ul><li>Playback is a reversal of this process, using a a digital-to-analog converter (DAC) circuit chip to play back the binary sound file. </li></ul><ul><ul><li>For more detailed information see How Sound Cards Work </li></ul></ul>
  35. 35. Storing Sound <ul><li>Sound waves are sampled at a constant rate (sample rate) </li></ul><ul><li>Amplitude (height) of the wave is stored. </li></ul><ul><li>The higher the sample rate the better the sound </li></ul><ul><li>The higher the sample rate the more data is stored </li></ul>Wavelength amplitude sample rate
  36. 36. Analog to Digital 16,777,216 65,536 Number of possible Output Levels 24-bit 16-bit Sampling Accuracy 192,000 44,100 Samples per second 192 kHz 44.1 kHz Sampling Rate DVD Audio CD Audio
  37. 37. Communications <ul><li>Computers communicate if they are electronically connected, have the appropriate software, and have common protocols or rules for negotiating their communication. </li></ul><ul><ul><li>Computers are digital, as are networks, but phones and wireless communications move data primarily as analog sound waves. </li></ul></ul><ul><li>Modems translate digital information to analog sound for transmission along telephone lines, and back to digital at the other end . They must synchronize speeds, block sizes, and correct errors during communications. </li></ul><ul><ul><li>Early modems were 300 baud (bits per second, or about 36 characters per second) 33.6 KBPS modems move over 4000 bytes per second. </li></ul></ul><ul><ul><li>Analog telephone lines are generally limited to modem speeds of 33.6 KBPS; new 56K modems and 64K to 128K ISDN connections make use some of the digital aspects of modern telephone lines. </li></ul></ul><ul><ul><li>DSL uses high frequency compression to achieve 1.5 mbps down; Cable Modems can deliver 30-40 mbps of _shared_ bandwidth </li></ul></ul>
  38. 38. Networking <ul><li>Many computers make digital connections to a local area network (LAN) or wide area network (WAN) via telephone lines (twisted pair), coaxial cable, fiber optic cables, radio, or wireless communications. </li></ul><ul><ul><li>Networks make it possible for large numbers of computers to communicate with each other, and to share resources such as files, applications, and devices . </li></ul></ul><ul><ul><li>Networks manage digital traffic by moving data as packets, with elaborate protocols for ordering or prioritizing them, checking errors, and filtering. </li></ul></ul><ul><ul><li>Local area networks can be configured as star networks, bus networks, or token-ring networks </li></ul></ul><ul><ul><li>Networks can be connected to WANs or to the Internet via modem, ISDN, cable modem, satellite, and other devices </li></ul></ul><ul><li>For more detailed information see How Ethernet Works </li></ul>
  39. 39. Network Configurations <ul><li>Bus Network connected to a Star Network </li></ul>
  40. 40. Electronic Mail (Email) <ul><li>Email allows users to send and receive electronic messages over any type of network or modem connection using a store and forward methodology . </li></ul><ul><ul><li>Messages are uploaded to the local mail server, passed to the recipient’s account on that server, or forwarded to an external mail server over a number of “hops” via intermediate servers. </li></ul></ul><ul><ul><li>Messages are downloaded by the recipient’s mail client from their mail server when the messages arrive, or when the recipient opens an active connection to that server from their client. </li></ul></ul><ul><ul><li>Depending on the type of mail service, messages may remain on the host mail server or be downloaded to the local computer. </li></ul></ul><ul><li>Improved bandwidth for networks and the Internet has made instant messaging and real-time chat a viable form of electronic communication, and is making voice-over-IP practical as well. </li></ul><ul><li>For more detailed information see How Email Works </li></ul>
  41. 41. Email Web Mail Server (HotMail, Yahoo, AOL, etc.) POP3 Server (your ISP) IMAP Server (UNT EagleMail) Proprietary data-based Mail Server (Exchange, GroupWise) Email Client (Outlook) Web Browser (IE or Netscape) IMAP Client (Outlook Express) POP3 Client (Netscape, OE) * Proprietary servers usually store email messages and attachments in a real database of some form * POP, IMAP, and some Web Email servers store email messages and text-encoded attachments as text files in most cases * Email moves between servers over SMTP * The user reads their email by using some sort of client software to connect to the mail server SMTP Connections SMTP Connections SMTP Connections SMTP Connections
  42. 42. Computers at Work <ul><li>The computer industry is HUGE with many opportunities in sales, development, manufacturing, training, implementation, support, and consulting </li></ul><ul><ul><li>Electrical engineers , electronics technicians, repairmen </li></ul></ul><ul><ul><li>Application designers, developers, support staff, instructors, consultants, technical writers, and editors </li></ul></ul><ul><ul><li>Graphics designers , special effects, art and film technicians, medical technicians, geosystems analysts, and any other job where the individual primarily processes computer-based information </li></ul></ul><ul><ul><li>System administrators , network administrators, database administrators, security analysts, communications specialists, and outsourcing service providers </li></ul></ul><ul><ul><li>Jobs related to the use of robotics in manufacturing </li></ul></ul>
  43. 43. Copyrights & Software Piracy <ul><li>Software publishers have always taken pains to protect their intellectual property. </li></ul><ul><ul><li>Most software is covered by copyright, meaning that it cannot be copied without special permission from the author </li></ul></ul><ul><ul><ul><li>Often there will be a specific statement that you can make a backup </li></ul></ul></ul><ul><ul><li>Most commercial software packages have elaborate licensing agreements, much more like leasing than buying </li></ul></ul><ul><ul><li>Shareware, freeware, banner ware, ad ware, and open-source software are all variations on the licensing of software </li></ul></ul><ul><ul><li>Public-domain software is not copyrighted, and is free to be copied and used </li></ul></ul><ul><li>Copying software outside the limits of the licensing agreement is a crime ; the Software Publishers Association (now called SIIA) has an extensive anti-piracy program and web site. </li></ul>